Mouse is formally Tiger's friend as seen in the episode Tiger and Mouse. She is voiced by E.G. Daily.
She is a gray mouse with long eyelashes and a pink tail.
The Mouse is portrayed as destructive, evident by her chewing apart every wire in the UG RV. She is also mean and selfish, immediatly ending her friendship with Giant Realistic Flying Tiger upon encountering the opportunity to date English Muffinz, a popstar she is obsessed with. She is also condenscending, insulting Giant Realistic Flying Tiger. Other than that, the Mouse acts like a stereotypical teenage girl, being obsessed with makeup, boys, and slumber parties.
- Mouse is voiced by E.G. Daily who is also very prominent for providing the voices of Tommy Pickles from "The Rugrats", Rudy Tabootie from "ChalkZone" and Buttercup from "The Powerpuff Girls."